diff --git a/lib/binary_to_decimal.rb b/lib/binary_to_decimal.rb
index 439e8c6..578cf26 100644
--- a/lib/binary_to_decimal.rb
+++ b/lib/binary_to_decimal.rb
@@ -5,5 +5,14 @@
 # Calculate  and return the decimal value for this binary number using
 # the algorithm you devised in class.
 def binary_to_decimal(binary_array)
-  raise NotImplementedError
+  decimal_number = 0
+  exponent = binary_array.length - 1
+  binary_array.each do |digit|
+    if digit == 1
+      decimal_number += 2**exponent
+    end
+    exponent -= 1
+  end
+      return decimal_number
 end
+puts "#{binary_to_decimal([1, 0, 0, 1, 1, 0, 0, 1])}"